Cathode ray multisignal measuring and recording apparatus



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cATRoDE RAY MULTISIGNAL MEASURING AND RECORDING APPARATUS WSze carol, J7? 34.44. errell L.L.Beye73J1: A.E1?obertson @M @QQ/@7M @www June 8, 1954 w. SHEPARD, JR., ETAL CATHODE RAY MULTISIGNAL MEASURING AND RECORDING APPARATUS Filed Nov. 26, 1947 '7 Sheets-Sheet 7 Patented June 8, 1954 UNITED STATES PATNT GFFICE CATHGDE RAY MULTISIGNAL MEASURING ANB EEGORDING APPARATUS Application November 26, 1947, Serial No. 788,307

6 Claims.

(Granted under Title 35, U. S. Code (1952),

sec. 266) This invention relates to cathode ray multisignal apparatus for measuring `and recording simultaneous variations in a plurality of signals respectively corresponding to variations in ia plurality of quantities. More specifically, the invention relates to means for producing six traces simultaneously on a moving film and corresponding respectively to signals caused by variations in quantities to be measured and projected on recording nlm in a transverse line with respect thereto by a plurality of cathode ray tubes While the fllm'is moving at a continuous rate of travel, an optical system being employed to direct images of the moving spots on the fluorescent screens `of the tubes onto the lrn.

In accordance with a preferred embodiment of the invention, a plurality of cathode ray tubes are preferably disposed in a row with their fluorescent screens preferably arranged in the same plane; individual amplifiers are associated with the cathode ray tubes whereby the signals control the deflections of the beams in the same plane, for example, the horizontal plane. A lens and mirror system focuses images of the indications on the screens into adjacent spaced positions on a movingfilm. Means are provided to move the lilm past the lens in the focal plane thereof at a uniform rate, thereby to provide continuous displacement time records of the spots on the screens of the cathode ray tubes and twodimensional traces on the film for the respective indications. Calibrating circuits are provided for the amplifiers, and switching means controlled from the film moving means is provided for deilectlng the beams off the fluorescent screens except when useful signals are being applied to the amplifiers.

In accordance with a preferred form of the invention sii; cathode ray tubes are provided for simultaneously producing six signal traces on the film, and in addition thereto, two other cathode ray tubes are provided for applying timing traces to the film, these two cathode ray tubes also having deflection amplifiers associated therewith. Means of conventional design is provided for supplying timed pulses to the deflection amplifiers of the cathode ray tubes which supply the timing traces. Additional supplemental circuits are preferably provided, for example, beam control and signal initiation switching circuits to conserve the nuorescent material on the screens of the tubes. A system of mirrors is provided for viewing the cathode ray screens, the system including a rotatable mirror adapted when rotated to provide two-dimensional images of the spots on the fluorescent screens.

The equipment embodying the subject invention is particularly constructed and arranged to provide portability and economy of size and weight. Special circuits in the amplifiers provide maximum sensitivity and stability with a minimum of component parts. A mirror and lens Vit) system permits mounting the Oscilloscopes and camera in a compact arrangement. An adjustable timing device operatively connected to the camera controls the .amplifiers and oscilloscope circuits in a manner to provide maximum eniciency of operation and longevity of the iiuorescent screens of the cathode ray tubes. A portable and compact power supply provides all necessary operating voltages for the tubes, and is suitable for use with commercially available power sources.

One of the objects of the invention is to provide new and improved means -for simultaneously producingvisual indications respectively correspending to variations in a plurality ol signals respectively corresponding to changes in a plurality of variable quantities.

Another object is to provide new and improved apparatus including a plurality of cathode ray oscilloscopes for simultaneously securing measurements of a number of varying signals.

Another object of the invention is to provide new and improved measuring and recording apparatus employing a plurality of cathode ray tubes and having an automatic beam control circuit for centering the beams of the tubes on the fluorescent screens thereof as the signals to be recorded are applied to the deflection plates, and thereafter decentering the beams when a predetermined period of time has elapsed, thereby to minimize wear of the fluorescent material of the screens.

Another object is to provide new and improved means for calibrating the amplier channels of a multiple trace cathode ray oscilloscope whereby the scale sensitivity of the screens and the gains of the amplifiers may be readily determined by inspection of the screens.

Another object resides in the provision o1" new and improved automatic timing circuits for use with an oscilloscope for controlling the initiation of the signals to be visually reproduced.

Another object is to provide a new and improved timing device for use with a recording cathode ray oscilloscope employing moving ii-lm, in which the timing device is automatically controlled by the same means which moves the film.

Another object resides in the provision of a new and improved deflection control amplifier characterized by high sensitivity and fidelity with 3 a minimum of parts, and particularly adapted for use in a portable cathode ray oscilloscope.

A further object is to provide new and improved apparatus for visually observing the indications appearing simultaneously on a plurality of cathode ray tubes.

A still further object resides in the provision of new and improved camera apparatus and optical system therefor for recording as two dimensional traces a plurality of spot indications of moving cathode ray tube beams, in which the movement of the camera film provides a time base for the indications.

Still other objects, advantages, and improvements not specifically set forth hereinbefore will be apparent after a consideration of the following specification taken in conjuntion with the accompanying drawings, in which:

Fig. 1 is a front View in elevation of a suitable housing for the apparatus of the preferred embodiment of the invention;

Fig. 2 is a side elevation of the housing and apparatus mounted thereon;

Fig. 3 is a vertical section through the housing and camera along the line 3 3 of Fig. 1, showing the general arrangement of the parts with- 1n;

Fig. 4 is a view partly in section and partly in elevation of the lm driving apparatus and mechanical timing apparatus operatively associated therewith;

Fig. 5 is a detailed cross sectional view of the arrangement of the micro-switches and other apparatus, taken along the line 5-5 of Fig. 4;

Fig. 6 is a detailed view of the gears and driving mechanism of Fig. 4;

Fig. '7 is an elevational view of the back of the front panel, showing the arrangement thereon of the chassis of the cathode ray tubes and amplifiers;

Fig. 8' is a view of a strip of film having six typical signal traces recorded thereon and in addition two timing traces;

Fig. 9 is a simplified schematic electrical diagram of one of the deflection amplifier circuits employed with the cathode ray tubes;

Fig. 10 is a diagram in block form of the cornplete electrical system of the invention exclusive of the indexing or titling circuit;

Fig. 11 is a schematic electrical diagram of the indexing circuit; and

Fig. 12 is a schematic electrical diagram of the beam control circuit.

Referring now to the drawings and more particularly to Fig. l thereof, there is shown a cabinet or housing generally designated by the reference numeral Ill, mounted on four shock absorbing supports of conventional design, which are shown at 53. Upon the sides of the housing Ifl are mounted handles 2| and 22 to facilitate movement of the equipment, one of the objects of the invention being to provide portable multiple trace cathode ray measuring and recording equipment. Mounted upon the framework of housing I0, preferably sloping to somewhat facilitate ease of operation of the controls thereon and maximum visibility of the instruments, is a main panel I2, and below that a somewhat narrow switching panel 32, the panels being held in position on the main framework by suitable screws or other means. Panel I2 has handles I8 and I9 fixed thereon to facilitate removal thereof from the housing I0.

Inside the housing I0, and fixed to the back of panel I2 by any suitable means, is a row of eight chassis, Fig. 7, "IC, IC, 2C', 5C, 4C, 5C, 6C', and 8C for corresponding channels or circuits 1, I, 2, 3, 4, 5, 6, and fl respectively comprising eight cathode ray tubes '.FT, iT, 2T, 3T, 4T, 5T, 5T, and 8T respectively and ampliers therefor. These chassis are detachably mounted upon the panel I2, and each chassis is precisely located in a predetermined vertical position thereon by two keys or guide feet, shown on the left of the chassis 3C, Fig. 3, and which may, if desired, fit into two shallow grooves, not shown, extending longitudinally across the rear side of front panel i2. The two end cathode ray tubes and amplifiers are provided for timing purposes, as will be hereinafter more fully elaborated. The six inner cathode ray tubes and amplifiers are provided to supply simultaneous measurements or indications of'variations in six signals corresponding to variations in six quantities, as will be hereinafter more fully explained. The controls for the eight amplifiers are included among the controls adjustable from the front of panel l2.

Two meters are provided, mounted in the upper left hand corner of the panel, Fig. l, meter I3 serving as the indicating device of a vacuum tube Voltmeter circuit included in the apparatus of channel or circuit l, meter I4 being an A.C. voltineter of conventional design for indicating the voltage of the .IPL-C. power lines supplying power for the equipment, in the embodiment shown v., A. C., 60 cycles.

The circuit of channel l for cathode ray tube 1T, Fig. 7, may be of conventional design. Knob 33 mounted on the front of panel I2, Fig. l, controls the focus of the beam of tube T, in any conventional manner well known to those skilled in the art to which the invention pertains, as by controlling the arm of a potentiometer connected in the cathode ray tube circuit. Shaft or set screw 34 controls the vertical centering of the electron beam of tube TIT by conventional means, as by controlling the arm of a potentiometer connected in the cathode ray tube or amplifier circuit. Knob 35 controls the horizontal centering of the electron beam of tube 7T, as by controlling the position of the arm of a potentiometer in the amplifier or cathode ray tube circuit, in a manner well known to those skilled in the art. Shaft or set screw 36 controls 'the beam intensity, as by controlling the arm of a potentiometer in the cathode ray tube circuit, as is well known to those skilled in the art.

As will be more clearly apparent as the description proceeds, means is provided for calibrating the various amplifier circuits. To this end, a very stable oscillator unit, Figs. 3 and 10, is provided, which is adapted to generate a voltage of selected frequencies and of substantially sinusoidal waveform. This voltage is supplied to the input circuit of an electron discharge tube amplifier in circuit l, which may be of conventional design, having a gain control in the input circuit, the setting of which is controlled by knob 3l. An adjustable Calibrating voltage is measured by meter f3, and is developed across an adjustable step attenuator having the setting thereof controlled by knob Se having scale 39 associated therewith. The output of the attenuator may be taken from connector plug 40 labelled External Cal, and the output of the attenuator is also applied by internal lead connections to the amplifier channels I, 2, 3, 4, 5, and 6, as will be hereinafter explained more fully. A binding post 4I is provided for securely grounding the circuit of channel l at a predetermined point therein, if desired.

The amplifier circuits of channels I, 2, 3, il, 5, and l, which control the beam deilections of tubes IT, 2T, 3T, sT, 5T, and ET, Fig. 7, respectively, may be similar, a simplined circuit diagram of one of the ampliiier channels being shown in Fig. 9. The circuit of channel l has a focus potentiometer le, the position of the arm of which is controlled by knob 4d; a vertical position potentiometer l5, the position of the arm of which is controlled by shaft or set screw i5 a horizontal or H position potentiometer il the position of the arm of which is controlled by the knob an individual intensity control potentiornetei` "i3 the position of the arm of which is controlled by shaft or set-screw 41; and a gain control potentiometer 1,2 the position of the arm of which is controiled by knob d8. A plug i9 is provided for bringing an input signal to the amplifier of channel l. In addition to the individual intensity control i3, the amplifier channel has associated therewith an intensity control "iii common to all the channels and which is controlled by knob 5d, and which will be subsequently described more fully. The circuit of Fig. 9 will be described in detail hereinafter and need not be now traced, it being suffi-- cient to point out here that it provides an amplifier of variable gain for one pair of deflecting plates of the cathode ray tube.

Channels 3, 5, and t may be substantially identical with channel l, having individual focus, Tv-pcsition, lE-position, intensity, and gain controls, and input connectors.

The right hand channel 8, as viewed in Fig. 1, has focus control 55, V-position control 55, i-I-position control iii, and intensity control 58, these being oi conventional design, and may be similar to the corresponding controls of channel 1. The aforementioned common intensity control, designated in Fig. 9 by the reference numeral "it, is a potentiometer having the position of the arm thereof controlled as aforementioned by knob 5S.

A step attenuator, not shown, is provided in conjunction with each amplifier of channels i, 2, 3, Il, E, and ii. These attenuators have a common control knob sil, Fig. l, having a scale or setting indicator associated therewith. The attenuators comprise resistance networks in the input circuits whereby the inputs to the amplifiers from the input terminals, terminal it oi ampiiiier l, for example, when switch @it is in Gain position, may be attenuated times 1.0 or times 0.1. Similarly, when the switch te is in Calibrate position, a Calibrating voltage is being applied to the signal amplifier channels from channel "i, and this Calibrating voltage may be attenuated times 1.0 or 0.1 depending upon the position of knob Gti. The knob Se, accordingly, is observed to have four positions. In each of the chassis IC, 2C, 3C, dC and 5C is mounted a multiple pole, four position switch, not shown, these switches being mounted in alignment when the chassis are mounted on panel l2, and the switch arms thereof being ganged, as by a long shaft common to all the switches and insertable through aligned apertures in all the chassis, all of the switch arms being controlled from knob Sil.

Also mounted on panel l2 is a beam control switch 6i for purposes to be hereinafter explained, and a binding post S2 for grounding the circuit of channel ii at a predetermined point therein, if desired. Below the main panel i2 is the aforementioned supplementary panel 32, having a number of switches and controls mounted thereon, these to be more fully explained subsequently.

The cathode ray tubs IT through 8T inclusive provide a maximum of eight simultaneous indications. The instant invention provides that six of these are signal indications and that all may be simultaneously viewed, or simultaneously recorded on film, as will hereafter be more fully explained.

Two methods of recording on nlm are provided for. To this end, a camera le@ is provided, detachably mounted upon the top of the housing iii, Fig. 2, the camera having handle idf and eX- tended langes |54 on either side thereof adapted to slip in the recessed portions of a pair oi guideways 52 mounted on the housing i on either side of the camera position and maintained thereon by screws it. The camera me, Figs. 3 and 4, has therein a lens aperture i i9 adapted when the camera lilo is mounted on the housing l@ to register with an aperture itil in housing iii. The camera itil further has therein a revolvaole drum I3 having raised side anges i225 and 22 and having thereon sprocket teeth iii? for engaging the sprocket holes ii, Fig. 8, in the film it.. This drum is mounted to rotate with a shaft H36 and is in a predetermined position with respect to an adjacent lens i3d, which is adapted in a manner to be subsequently more fully described to focus images onto the film it which has its outer surface in the focal plane of the lens. A supply reel lli journaled for rotation on shaft H3, which is mounted in the camera les, has a pulley groove H6 formed integral therewith, and is coupled by a spring belt H5 to a take-up reel H2 having pulley groove lll integral therewith, the reel being journaled for rotation upon shaft lili also mounted in the camera it.

The drum HB3 may be adapted to have a bearing therein for shaft iiii, the shaft having a suitable keyway, not shown, therein adapted to cooperate with a key, not shown, in the bearing, so that the drum may be slideably removed from. the shaft, pressure of spring 521i, Fig. 4, upon member |23 providing for maintaining the drum in place upon the shaft. Rotation of the drum causes movement of the film from the supply to the talcoup reels, as will be readily understood by those skilled in the art.

The small housing E3? is disposed within the camera ldd for mounting the aforementioned lens E36 and the mechanism for operating shutter E43 associated therewith. The housing i3? has a relatively heavy and solid upper portion or top [4| having a threaded bore M2 therein for receiving a lens adapter 35 which has a ange portion 38 for convenience in inserting the adapter into the aforementioned bore. The adapter has a lens barrel Mid for the lens 3G and which is adapted to be inserted into the lens bore. in the adapter, thereby to provide a mounting for the lens. Focusing is accomplished by turning the lens adapter in its threaded bore iii?. whereby the lens is moved closer to or farther from the film |65 as may be desired. Whereas any suitable lens may be employed, in the preferred embodiment herein described the lens is a Bausch and Lomb Baltar wide angle lens. rEhe lens may be, if desired, provided with an iris diaphragm suitably adjustable for adjusting the speed of the lens.

Mounted upon the underside of top plate iii are two bearing member illi and idg having small spur gears H and i526 meshing and mounted for rotation thereon respectively. Gear has used thereto the aforementioned lens shutter M3 adapted to move with the movement of the gear 145, Gear M5 is adapted to mesh with the teeth |55 of a rack |5l which is slideably mounted on the underside of plate HH and extends through an aperture or opening beyond the camera wall, to form a shutter operating means manually operable from outside the camera.

Film perforating means of conventional design, not shown, is mounted in the back wall of the camera to provide means for identifying the film, and for other purposes.

Reference is made now particularly to Fig. 3, on which is shown details of the apparatus by which the indications on the fluorescent screens of the cathode ray tubes are reflected through aforementioned lens 535 within lens barrel i134 on to the aforementioned nlm ille, or viewed by the eye of an observer at viewing hood or eyepiece l5, Fig. l. There is provided a system of mirrors mounted within the housing lil in predetermined positions therein, and adapted to provide paths Y and X for the light rays from the fluorescent screens to the nlm or eyepiece respectively.

The mirror 35B, which provides for path Y, is a relatively long, at mirror extending along the rear of housing it, and is mounted upon a fiat supporting member 353 which is in turn mounted upon brackets at each end of the housing, one of the brackets being shown at 35s and held to the base of the housing by screws The mirror is securely held to member 353 by suitable mounting brackets such as 352, which are iixed to member 353 as by screws 35i.

Light rays originating at the fluorescent screens of cathode ray tubes ET, 2T, 3T, iT, 5T, bi, iT, and 3T are reiieeted by mirror Stil through aforementioned apertures I i9 and H2B to the lens it in lens housing 235 and thence to film 35.

The aforementioned eyepiece or hood l5 is provided for viewing the fluorescent screens, is 'lined to the front panel l2 by any suitable means, and is in registration with an aperture 2131i in the panel. A shutter 283 is provided for closing the aperture when the eyepiece is not in use, the shutter sliding in guide pieces 285 and 286 xed to the rear of panel l2 by screws i237 and 283 respectively, Figs. 3 and '7. The shutter has a handle il', Fig. l, securely xed thereto as by screws tti and nut 282, Fig. 7, and which extends through a slot it in panel i2, the handle providing means manually operable for manipulating the shutter to close and open aperture 2M.

The path X is provided for by mirrors 34 l, 321, and 332 which, in Fig. 3, sequentially reect images of the indications appearing on the fluorescent screens to the eye oi an observer disposed at the eyepiece i5. Mirror 3i! is mounted upon a long, fiat base member' SM1 which in turn is mounted upon a back wall 3l! of housing lil by brackets such as fixed to the wall as by screws The mirror Sill is held to its base 3M by bracket 3&3 suitably xed thereon as by screws 342.

Mirror 32! has a mounting plate 322 xed to the upper or side walls by any suitable means,

not shown, and is fixed to the mounting plate by brackets such as held to the plate as by screws 324.

Mirror 332 is mounted upon a suitable support 355 and fixed thereto by any convenient means not shown, the support 335 being adapted to be rotated about its longitudinal axis, Three other mirrors ani. are mounted upon the support 335 with their reflecting faces disposed as shown in Fig. 3. .lt will be recalled that signals applied to the amplifiers of channels i through i3 renect the cathode ray tube beams only a horizontal direction or plane. 1t will be understood by those skilled in the art to which the invention pertains that rotation of the member 33d, whereby mirrors 33H, 335i, and 334 in rapid sequence reflect the images on the screens te the eye, provides for the production of two dimensional images to an observer stationed at eyepiece le.

The support 335 may be rotatably mounted within the housing in any convenient manner, as by suitable bearings suspended from the walls or top of the housing. The member 335 has operatively connected to the endy thereof a member 2t, Figs. i and 2, which is adapted to be manually rotated thereby to rotate the member 335 and mirrors 335, 333, and 33t iixed thereon. Preferably the support 335i has operatively connected thereto a large, solid relatively heavy member, not shown, adapted to rotate therewith and provide a flywheel effect.

Referring now particularly to 4 which shows the apparatus for rotating the aforementioned drum shaft its, the drum shaft is journaled for rotation in a bearing lili mounted w; hin a small housing 25 fixed to the inside of wall $23 of camera lili] by rivets 52e. The bearing mein er iii! is adapted to be inserted through a bore ist in the wall E23 so that the flange abuts againstA the wall 23, and

- through a corresponding or registering bore in housinCr 525, and has a threaded end for receiving nut l2? for holding the bearing xedly in place in the housing lil. rhe shaft ist extends outside the wall where it has fixed thereon a sprocket wheel i313 and an adjacent pulley 32. The sprocket wheel i3@ has a chain i233 driven thereby which drives a. mechanical counter of conventional design, generally designated by the reference character i232, Fig. 2, and fixed to the wall of camera iil. Pulley 32 is driven by a belt B8 from pulley 8G, Fig. 1, which is driven through variable speed transmission 6i from a motor H. .attached to the camera wall, Fig. 2, is a spring tensioned idler pulley generally designated by the reference numeral i5?, for maintaining tension on belt 63. The motor l l and variable speed transmission are mounted upon a base l'! which is mounted by shock absorbing supports, which are shown at 55, iig. l, upon the top of the main housing lil. The variable speed transmission may be of conventional design; in the embodiment shown, a transmission known in the trade as a Graham mode 15M type A9091?, is employed. A clutch having arm sii and operating lever @t is adapted to shift pulley dii from a driven to an idle position, in a manner well known to those skilled in the art. The raised shoulder e8 of the base il' has mounted therein a switch 56, Fig. 2, adapted to have its contacts selectively closed or opened depending upon whether arm 69 is thrown to a drive or idle position respectively, the switch acting under certain conditions, hereafter to be described., to center or direct the beams oi all the cathode ray tubes on their iluorescent screens.

As is well known in the art, it is usually undesirable to leave the beam of a cathode ray tube focused on the fluorescent screen in unmoved position and in suflicient intensity for a considerable length of time, for the reason that the uo- ,rescent material may be burned off. Prior art .devices have usually employed. electrical circuit means to decrease the intenstiy of the beam and the brilliance of the spot during those periods when no useful signal was applied to the cathode ray oscilloscope. The instant invention provides an improved arrangement in which, during periods of idleness when no signal to be recorded is applied to the scope, a high defiecting potential difference is applied between one pair of plates suiicient to deflect the beam completely off the iiuorescent screen. Circuits are provided whereby when beam control selector switch 23 on panel 32, Fig. 1, is thrown to its Clutch position, throwing the clutch lever 69 to a drive position starts the movement of film past the aforementioned lens |39 and at the same time operates the aforementioned switch |90 in shoulder 98 which results in the movements of the cathode ray tube beams to center positions. When clutch lever 99 is moved to an idle position, the beams are deflected oif of the fluorescent screens.

A solenoid 94, mounted in a bracket 91 beneath shoulder 99 is operatively connected to arm 95 and is adapted when energized to throw the clutch from an idle to a driven position. Lead connections to the solenoid 94 are brought through leads 10, Fig. 2, to suitable terminals on the terminal strip 3|, Fig. 1.

The drum |03, in addition to being adapted to l have a nlm move therearound as it moves from supply reel i i to take-up reel |2, at a speed determined by the setting of the variable transmission 91, is also adapted, if desired, to have a length of nlm attached around the outer periphery thereof, the end of the film overlapping, and the nlm moving unbrokenly past the optical axis of the lens in the focal plane thereof. When such an arrangement is employed, it is desirable to provide automatic switching means for centering the beams during one revolution only of the drum and thereafter instantly deflecting them oif of the screens, in order to insure that the traces formed on the nlm by images of the moving luminous spots on the fluorescent screens do not overlap and become distorted and confused on subsequent drum revolutions after the first.

To this end, a mechanical timer is provided, shown in Figs. 2 and 4 mounted upon the top of the housing Hi at the rear thereof adjacent the camera |99, and having the general designation 113|. A. base |92 has flanges 95 and 89 on the bottom thereof having bores for receiving screws 91 and 99 respectively for securely fixing the base to the housing I0. The right end of base |62 has the shaft |61 having a smooth extension or uncut portion on the left end thereof, Fig. 4, on which is journaled and free to rotate thereon an arm 209, the arm 299 having a stud shaft or bearing member 22| nxed thereon for mounting a gear 2|@ which is free to rotate on the bearing member. Outside the arm 209 and fixed to worm shaft |91 to rotate therewith is the gear 2H,

adapted to mesh with gear 2|0. In the lower end of the arm is :iixed a screw 299 adapted to passv through a cut-away 206 in plate 295 and having locking nut 291 threaded thereon, the screw and locking nut being provided for fixing 10 the position of arm 209 with respect to plate 205. When plate 205 is mounted in the position shown in Fig. 6, gear 2|0 meshes with a gear 2|2 Xed to shaft |06 to rotate therewith. Accordingly, movement of the belt 68 and pulley |32 drives the lm and also causes rotation of the worm shaft |91 through the chain of gears 2|2, 219, and 2| l. When it is desired to detach camera |90 from the housing l0, nut 201 is loosened and arm 209 swung to a position where gear 2||l may be freely disengaged from gear 2|2.

Adjacent the worm shaft |91 are mounted two other shafts |66 and |96, with the axes of all three shafts mutually parallel. A cam or worm follower generally designated at |99 is adapted to move freely upon the shaft |66. The follower has an arm |98 having an aperture |91 therein through which the shaft |95 passes, and the arm |98 has xed thereon a tooth |95 adapted to engage the threads in the worm shaft |51, whereby the follower |99 is moved to the right or left, Fig. 4, in response to rotation of the worm shaft. In actuality, in the operation of the apparatus, movement of the follower is always toward the right, Fig. 4, as will be explained more fully subsequently.

Two additional parallel shafts |69 and |99 extend between the plates 205 and |64, these being positioned below the worm shaft, Figs. 5 and 6. Shaft |98 is threaded throughout substantially its entire length, while shaft |69 is not threaded. Mounted upon these two shafts is a metal block |12 having a threaded bore |15 therein for receiving threaded shaft |69, and a smooth bore |19 therein through which shaft |69 is adapted to movably pass. Mounted upon block |12 is a switch |19, held in position thereon by a plate |11 on the right side thereof, Fig. 4, the plate being fixed to the switch |19 by screws |13, and being fixed to the block |12 by screws |18.

The switch |19, the purpose of which will be hereinafter explained, which may be of the type known in the trade as a Microswitch, has an arm |90 mounted thereon adapted when moved downward, to depress a pin |9| which operates the switch mechanism. This arm |80 is adapted to be actuated by a stud or shoulder piece 203 carried by the worm follower, when the worm follower has moved into position about the switch. The switch |19 is adapted to be moved to the right or left, Fig. 4, by rotation of shaft |99, which has xed on the right end thereof, Figs. 2 and 4, a dial 99 held thereto by screw 90, the dial having markings thereon for precisely positioning the switch |19, forreasons to be subsequently apparent. An indexing scale |10, Fig. 4, is mounted parallel to shafts |68 and |69 and held in place by screws, one of which is shown at the mounting bloei; |12 of switch |19 having an index marl; |89 thereon which is adapted to cooperate with the markings on |10, member |10 in conjunction with dial E9 providing for precise positioning of switch |19, the 100 divisions of dial 89 corresponding to l small division on scale |10 in the embodiment shown and described.

rIwo other switches |89 and |99 are provided, positioned at the right hand end of the rnechanical timer, Fig. 4. They have arms 2id and 2|| respectively, and pins 2|3 and 2id respectively, the arms being adapted to be operated by shoulders 20| and 202 respectively of worm follower |99, as the follower moves into positions adjacent the switch arms. As previously explained, the worm shaft |61 upon which the 4vworm follower or cam |99 moves, is geared to rotate with shaft |26 which rotates the drum |23 upon which the film moves. The positions of switches is@ and |89 are in practice carefully chosen so that the distance between their arms is substantially that which the worm follower or cam travels along drive screw |83 during one revolution of the drum |03. These switches, when the circuits are so connected, in manners to be subsequently explained, control the centering of the cathode ray beams on the iluorescent screens of the cathode ray tubes, switch |90 when operated centering the beams, and switch |29 when operated decentering the beams. Leads Si? to switches |98 and |89 are joined by leads |24 to switch H2 to form cable 82, Fig. 2, and which connect with various parts of the electrical circuit as shown in Figs. 9, 1G, and 12, the cable having connector 83 associated therewith.

The shaft |26 is eccentrically mounted, being fixed by pin 222 to a lever 223, Fig. 2, adapted when lifted to raise the shaft |96 and release the tooth |95 of the worm follower from contact with the worm. Lever 223 has a pin fixed therein having spring 225 anchored thereon, the spring being ixed at its opposite end to pin 225 fixed to plate |64, the spring acting to normally maintain the worm and worm follower in contact or operative positions.

Reference is made now to Fig. 9, which shows an aforementioned simplified Schematic electrical diagram of the amplifier circuit employed with channels l, 2, 3, 4, 5 and 6, and generally designated by the reference numeral 232. As previously stated, one of the objects of the invention is to provide multiple trace cathode ray oscilloscope equipment which is portable and has little weight. To this end, the amplier circuit of Fig. 9 is provided, which represents an irnprovement over conventional deflection amplier circuits in that high gain is secured with a limited number of electron discharge tubes, marked stability and freedom from drift are provided, and the amplier has in the embodiment herein described a uniform response from D.C. or Zero cycles/sec. to 40,000 cycles/sec.

An aforementioned conventional. input gain control potentiometer 12, has one end thereof grounded at 23'! and connected to the control grid of an electron discharge tube 232, which may be a pentode known in the trade as type y BSJ'?. The arm of the potentiometer is similarly connected to the control grid of another pentode 23| which may be of the type BSJ'Y. The input signal is impressed across the entire potentiometer resistance. The suppressor grids of the pentodes are connected to their respective cath odes, and the cathode of tube 23| is connected to resistor 225, thence through the entire resistance of balancing potentiometer 238, thence through resistor 236 to the cathode of tube 232. The anode of tube 22| is connected to resistor 233, thence through the entire resistance of aforementioned H-control potentiometer 1| thence through resistor 23d to the anode of tube 232. The arm of potentiometer 1| is connected to the positive terminal of a source of D.C. potential, which may be of the order of +215 volts to ground, while the arm of potentiometer 238 is connected in series with resistor 245 to the negati-ve terminal of a source of D.C. potential, which may be of the order of -215 volts to ground. rfhe screen grids of tubes 23| and 232 may be connected together and to the positive terminal of a source of D.C. potential which may be of the order of +75 volts to ground.

\ to the beain position switches.

A Second stage comprises electron discharge tubes 23?! and 249, which may be pentodes of the type known in the trade as 655117 The control grid of tube 239 is connected to the anode of tube 23|, while the control grid of tube 240 is connected to the anode of tube 232. rEhe suppressor grids of tubes 239 and 246 are connected to their respective cat-nodes, and the cathode of tube 232 is connected to resistor 24| and thence to resistor 2132 and thence to the cathode of tube 240. Resistors 24! and 2&2 have connected in parallel therewith respectively capacitors 243 and 2134. The junction between resistors 24| and 242 is connected through resistor 2155 to the negn ative terminal of a source of D.C. potential which may be of the order of +340 volts to ground. The anode of tube 239 is connected to resistor 259 and thence to resistor 26d and thence to the anode of tube 245i, and the junction between resistors 259 and 265i) is connected to the positive terminal of a source of D.C, potential, which may be of the order of +460 volts to ground. The anode of tube 239 is connected to one of the horizontal defiecting plates of cathode ray tube iT, while the anode of tube 211i] is connected to the other horizontal deflecting plate of tube iT. The junction point between resistors 259 and 26) is connected to one end of a resistance or voltage divider 25| having points or taps 252, and 251i, thence to ground at 253, thence through resistor 255 thence through the entire resistance of aforementioned focus potentiometer ld thence through resistor 251 thence through the entire resistance of aforementioned individual intensity control potentiometer 13 thence through the entire resistance of aforementioned colnmon intensity control potentiometer it to the negative terminal of a source of D.C. potential, which may be of the order of 1240 volts to ground. Across the ends of potentiometer 'it is connected a gas discharge tube 26|.

The arm of individual intensity control potentiometer 'i3 is connected to the cathode of cathode ray tube iT. Tube iT may be of the type known in the trade as a 2BP11, having in addition to a iilarnent, cathode and deflecting plates, three elements 235, and 261 adapted to influence the electron stream. The arm of focus control potentiometer 'it is connected to the element 286 of tube 1T. The arm of common intensity control 'is is connected to element 26'! of tube iT. Element 265 of tube ET is counected to point 252 on resistor 25|, and is further connected through lead A to a beam position switch circuit, 12, and is also connected through resistor to the lower one oi the vertical deflecting plates of tube iT. This lower one of the vertical deilecting plates is also connected Across points 252 and 254 on voltage divider 25| is connected an aforementioned V position control potentiometer l5, the arm of which is connected to the upper vertical deflection plate of cathode ray tube iT.

The circuit of tubes 23 i, 232, 239, and 245 coinprises a balanced D.-C. amplifier of high stability. It is noted that tubes 23i and 232 comprise a cathode coupled amplifier, in whch phase inversion occurs in the cathode circuits of the tubes. The input stage also provides a balanced amplifier with single ended input; a variation in the plate voltage of the tubes does not cause a change in the output of the stage. It is further noted that the final stage provides a negative feedback arrangement to compensate for losses in high frequencies, the small cathode resistors providing negative current feedback. 'These resistors 253 and 242 may be of the order of 850 ohms each. They are preferably by-passed as show-n by small capacitors 2&3 and 241i respectively, which may be of the order of 0.01 mid. each, and which improve the frequency response of the amplifier, which, by suitable choice of component values, may be made to have a ilat response from zero to 48,000 C. P. S. In the preferred embodiment herein described, the amplifier provides a voltage gain of approximately 3G00.

The common intensity control 'it having control knob 5S on the iront panel l2 is provided for adjusting the intensities of all the beams to desired values according to whether the equipment is idle or is being used for recording or observation purposes.

Reference made now to Fig. l), which shows s a schematic circuit arrangement partially in block form of the electrical system of the preferred forni of the invention. A regulated power 'supply 2?3 or any convenient design is provided for supplying the various operating potentials ed to be controlled from the iront panel Si; by

switch 2E, which, when iirst turned to its Heaters position, turns on the heaters oi the rectier tubes of the power supply and the heaters or filaments of all tubes. In the operation of the apparatus, after a suitable time interval during which the filaments are allowed to assume operating temperatures, switch 2t is turned to its Plates position, where it supplies the necessary anode potentials. Pilot lamps 2l and 23 may be green and red respectively and may indicate when the switch 2d is in its Heaters and Plates positions respectively. Meter lli, Fig. 1, is connected to read the voltage across the llo v. A.C. line, it being desirable to operate the equipment from an Aff). source of which the voltage varies only within predetermined limits.

The power supply 213 is designed for maximum portability and compactness, and may by suitable choice of component parts and arrangement thereof be made somewhat smaller than housing it, Fig. l.. Switch on the panel 32 is provided for turning on and on the motor l l.

As hereinbefore stated, an oscillator 2i l, which may be of conventional design, is provided for generating Calibrating voltages and timing iin pulses. Three frequencies are provided for, in the embodiment shown 40, 200 and 1000 cycles per second, the frequency of oscillations being controlled in any conventional manner by switch 3l) mounted on panel 32. The output oi the oscillator 2li is delivered to an aforementioned variable gain amplifier, which is designated in Fig. 10 by the reference character ist, the output of which is measured by aforementioned meter i3 and applied to an aforementioned attenuator, which is indicated in Fig. l0 by the reference numeral Mil, and which has its output controlled in steps by the aforementioned knob 3'3, Fis. 1.

The output of the oscillator l, which is preferably of sine wave shape, is applied to a clipper circuit 212 which may be of conventional design, where square waves are generated and simultaneously applied in phase opposition to the' ampliers of timing channels 1 and t, vwhere they provide markings on the film W5 correspending to traces 313'! and tt thereon, Fig. 8, the lengths of the markings increasing for a given iilm speed as the frequency of oscillator El! is decreased.

Referring again particularly to Fig. li), the six signal amplier channels l, 2, 3, il, 5, and 5 are shown, each comprising a cathode ray tube, an aforementioned amplifier 23d having gain control it comprising potentiometer 'i2 of Fig. 9, and an aioredescribed variable attenuator operated from knob 6i) of Fig. 1, which permits the input to all the ampliiiers to be controlled by a common control, whether the amplifiers are receiv ing signal voltages or Calibrating voltages, the intensity of all of the beams being controlled from aforementioned common intensity control l.

The calibration circuit described hereinbefore is employed for calibration of the channels. Assume, by way of example, that it is desired to employ one channel to record variations in a signal of relatively large amplitude, whereas it is desired to employ another channel to record variations in a signal ci small amplitude. The individual gain controls of the ampliers, in conjunction with the aforementioned step attenuators, permit production of traces on the nlm m5 which have relative scale values which are known with respect to each other, in a manner well known to those skilled in the art to which the invention pertains. The use of the Calibrating voltage also permits ascertaining by comparison methods the amplitude of a signal of unknown amplitude, as will readily be understood.

The switching circuit for centering and decentering the beams may now be fully traced, and comprises the clutch operated switch Hill, switches its and 96 of the mechanical timer, beam control switch tl, and beam control selector switch 23, all of which are interconnected in the circuit of Fig. 10, details of the connections being shown in Figs. 9 and 12. The operation of these switches is as follows: The beams may be centered at any time by throwing switch di to its Center position, and this switch is used to center the beams while adjusting or Calibrating the apparatus. When switch t! is thrown in its Oil position,

it connects lead B, Figs. 9 and l2, to the arm of clutchedrurn selector, switch 23. When beam control selector switch 23 is in its Clutch position, clutch switch lil-il centers or decenters the beams selectively in accordance with whether the clutch is in a drive or idle position; when beam control selector switch 23 is in Drum position, the beams are centered upon the operation of switch lili), and decentered by the operation of switch E39. Switches ist and its are normally in the positions shown in Fig. 12. When actuated in response to the movement of the aforementioned cam or worm follower lat, they are thrown to their other positions respectively during the period in which the cam is in contact with the respective arms 2id and 2 I4. It is noted that there is a time interval during which switch i90 is closed to the right, Fig. 12, and switch it is simultaneously closed to the left, Fig. 12. Clutch switch 53 is shown connected by leads 8|, Fig. 2, to the remainder of the electrical circuit.

An aforementioned switch |79 included in the mechanical timer is provided for initiating an occurrence which provides a signal to be recorded and measured. In Fig. 10, the switch V19 is connected by lead 398 to control an energy or signal switch 6T tlnownv tof a position to' center the beams of' all the cathode ray tubes', the beams are adjusted by aforementioned verticaly and horizontal controls to be properly positioned, and by aforementioned focus and individual intensity controls for proper visibility. Switch i is then moved to a position and knobs and ill adjusted to positions whereby a calibrat'ing signal of desi ed ainplltude is applied to the channels from channel l, and the gains" of the amplifiers of channels I-6 adjusted.A Switch di is then thrown toI its Off positiony and switch B3" is thrown to one of its Gain positions. l`he camera is' loaded properly. Switch Sil is adjusted to give timing traces' of desired length on the lm. The motor l! is' then and the variable speed transmission adjusted' to the' position which willi drive the ilmat the desired speed Beam controllseiector switch 23l isthrown to its Clutch position. The apparatus to be studied is then set in operation and subjected to vibration. The clutch lever is then thrown to its operating position, which starts the movement oi' film past the lens and through aforementioned switching circuits including switch itil causes the beams of the cathode ray tubes to b'edirected onto the fluorescent screens thereof, with the result that traces are recorded on the iilm. After a desired time interval has elapsed, thev clutch lever is thrown to its idle position, which' stops the movement of the nlm, and decent-ers t le' beams. The film then be `titled ifde'sired, by the use of aforementioned titiing apparatus, or the nlmi may be titled to the recording of the signals, if desired.

In the second mode oi operation of the device, the mechanical timer is employed. ri'he beams and amplifiers are adjusted in manners heretofore described. The switch 23 is thrown to its Drum position. A strip of is attached to the drum l, and held thereon by any suitable means, for example, transparent adhesive tape. Switch Vis is connected to the source ofthe signal or' signals to be` recorded, The apparatus isthen set in operation. The camera drumL is set in rotation by throwing the clutch lever to operate position. Switch lle initiates the signal to be recorded, and after a time' interval has elapsed, the length of which is determined by the position of switch lill as ad justed by aforementioned setting means including shaft i453' and dial Se, switches itil and itt are' operated and sequentially act to direct the beams onto the fluorescent screens during one revolution of the drum and thereafter deoenter thev bea-nis, during whichv revolution the signals to be recorded and measured are applied to the inputs of the" respective amplifier channels, it being assumed that thetirne interval to which the mechanical timer is set corresponds to the time required for generation of the signals tov be recorded. lt is of course understood that the signal initiation circuit of switch H9 may be dispensed with if desired in the study of signals of brief duration, the remainder of the mechanical timer being used in its normal fashion.

Whereas the invention has been shown and described with reference to a preferred embodiment thereof which gives satisfactory results,

it will be understood by those skilled in the art towhich the invention pertains, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, in the appended claims to include all such changes and modifications.

This invention may be manufactured and used by" or for the Government of the United States of .inerica for governmental purposes without the payment of any royalties thereon or ltherefor.`

What is claimed as new and desi ed to be secured by Letters Patent of the United States 1s:

i.. In cathode ray multi-signal' incas ring and recording apparatus of the character' disclosed, a plurality' of cathode ray 'tubesV having orthogonal-aires deflection systems individual thereto, said deiiection systems being adapted to deflect the electron beams of the tubes along one axis thereof inv response tol a plurality of signals respectively applied thereto, circuit means common to said deiiecting systems and including a pair of switches arranged in spaced relation and operable for directing the electron beams onto the fluorescent screens of the tubes or deecting said7 beams off of said screens along the other axis of the defiecting systems selectively in aocordance with the actuation of said pair of switches, a rotatable drum having a sensitive nlm mounted thereon around the outer periphery thereof, said drum being mounted upon a rotatable shaft, means for rotating said shaft, means for simultaneously focusing onto said nlm spaced` colinear images of the fluorescent traces of said beams normal to the tangential direction of :fnotion of said ii`n, a worm shaft geared to the rotatable shaft adapted to rotate therewith, said worm shaft being disposed in predeterminedpositon with respect to said pair of switches, and a worm follower for said worm shaft adapted to actuate said pair of switches in predetermined sequence as it moves along the worm shaft, the distance between said switches being such that said beams are centered on the uorescent screens during one revolution only of said drum.

2. in a cathode ray multi-signal measuring and recording apparatus of the character disclosed, in combination; a plurality of cathode-ray tube means adapted to Asin'iultaneously produce a plurality of linear indications corresponding to variations in a plurality of quantities; a normally open switching circuit connected to said cathode-ray tube means and adapted when closed to render all said cathode-ray tube means operable to produce said indications; a rotatable shaft; a moveable drum fixed to said shaft for rotation therewith and adapted to have a sensitive lm fixed thereon around the outer periphery thereof; means for focusing into spaced colinear positions on the periphery of said drum and normal to the peripheral center line thereof images of all said indications; meansfor driving said shaft; and means for closing and opening said switching circuit in predetermined sequence thereby to render said cathode ray tube means operable'for a predetermined period of time, said last named means including a Worm shaft, gear means operatively connecting said worm shaft to said rotat able shaft whereby the shafts are rotated together at speeds having a predetermined ratio, a Worm` fol-lower operating with said worm shaft, and a pair` of switches connected in said switching circuit and positioned in predetermined spaced relationto said worm shaft, said switches being adaptedto lie-sequentially operated by said wormV follower as ity moves in response to the rotation of said worm shaft to close and thereafter open said circuit.

3. In cathode-ray multi-signal measuring and recording apparatus of the character disclosed having a plurality of cathode-ray .tubes each having a iluorescent screen, in combination; a housing having nrst and second apertures therein; a camera having a lens, means for moving a sensitive lm past the lens in the focal plane thereof at a uniform rate of speed; said camera being adapted to be detachably mounted upon said housing with the lens adjacent said rst aperture; a first mirror disposed within said housing in predetermined position with respect to said cathode-ray tubes and said first aperture and adapted to reflect images of the indications of all the fluorescent screens into said lens when said camera is mounted on the housing; second and third mirrors mounted in said housing in xed spaced positions therein; a rotatable multi-faced mirror mounted in said housing adjacent said second aperture; in the optical path of the second and third mirrors whereby they are adapted to reect images of the indications appearing on all the screens of said cathode-ray tubes upon said rotatable mirror thereby to provide multidimensional indications of all traces when viewed from said second aperture; manually operable means external to said housing and connected to said rotatable mirror for rotating the mirror at will thereby providing two-dimensional images of the indications on the cathode ray screens; and adjustable cover means for selectively closing said second aperture.

4. In cathode-ray multi-signal measuring and recording apparatus of the character disclosed, in combination, a housing having an aperture therein, a plurality of cathode-ray tubes mounted in a row within said housing; a plurality of deflection amplifiers for said cathode-ray tubes respectively whereby a plurality of simultaneous colinear indications may be obtained on the fluorescent screens thereof; a camera 4having a length of film, film transporting means, and a lens, said transporting means including supply and takeup reels for said lrn, a rotatable drum adapted to have said nlm move around the outer peripheral surface thereof from said supply to said take-up reel when said drum is rotated, and a rotatable shaft xed to said drum for rotating the drum; a first pulley fixed to said shaft eX- ternal to the camera, the camera being mounted upon said housing with the lens adjacent said aperture and for iilm motion normal to the colinear images of said indications, mirror means mounted within said housing for reflecting images of all said indications into said lens when said camera is mounted on said housing; a motor mounted upon said housing; said motor having a variable speed transmission, a driving pulley, and clutch mechanism adapted to shift said driving pulley from an idle to a driven condition selectively in accordance with the operation of the clutch; a belt connecting said driving pulley and said nrst pulley for driving said shaft and drum; and means including a switch operatively connected mechanically to said clutch and electrically to said cathode-ray tubes for rendering said tubes inoperable to supply indications for said iilm except when said clutch is in an engaged position whereby said driving pulley rotates said drum.

5. In cathode-ray multi-signal measuring and recording apparatus of the character disclosed, having eight cathode-ray tubes, said cathoderay tubes being disposed in a roW at substantially' equally spaced intervals and with their fluorescent screens lying in the same plane, in combination, eight deflection control amplifiers for said cathode-ray tubes respectively, said deflection amplifiers all being adapted when energized to cause colinear beam deflections in said plane in accordance with signals applied thereto, means for continuously generating a variable frequency timing voltage having a substantially square waveform, means for applying said voltage in phase opposition to the ampliers associated with the outer two of said cathode-ray tubes, a camera having a supply of sensitive film therein, means including a lens for focusing onto said film in predetermined spaced positions thereon colinear images of the indications on the fluorescent screens of all the cathode-ray tubes, means for moving said film past said lens in the focal plane thereof at a substantially uniform rate of speed to produce signal measuring and timing traces thereon of said images, means for simultaneously centering a plurality of normally on centered beams and initiating operation oi said film moving means, means for defiecting said beams during predetermined limited operation of said film moving means, the movement of said film providing a time base for the indication images recorded thereon, and a plurality of means associated with the amplifiers of the other six cathode-ray tubes for adjusting the individual gains thereof to conditions where given transverse distances on said nlm represent predetermined signal voltages applied to said ampliers, said timing traces supplying reference means for ascertaining the common time base of the recorded images as supplied by the movement of said film.

5. The method of recording from a plurality of cathode ray tubes beam deflections, said deflections corresponding to simultaneous variations in a plurality of signals on a moving sensitive lm as a function of Atime comprising the steps of perforating the film while stationary for identiiication, initiating motion of said film and simultaneously applying potentials to the plates of said cathode ray tubes for deecting said beams in register with said film during predetermined limited motion thereof, applying said signals to said tubes for recording on said film, thereafter deflecting said beams out of register with said nlm and simultaneously ceasing motion of said lm upon termination of recording whereby mutually spaced images of deflections corresponding to said signal variations are recorded colinearly and normal to the direction of motion of said film.

References Cited in the file of this patent UNITED STATES PATENTS Nrunber Name Date 1,736,456 Matthias Nov. 19, 1929 1,893,337 Patterson Jan. 3, 1933 1,958,897 Leyland May 15, 1934 2,186,268 Pahala Jan. 9, 1940 2,241,432 Von Ardeche et al. May 13, 1941 2,251,786 Epstein Aug. 5, 1941 2,301,199 Bruce et al. Nov. 10, 1942 2,425,003 Potter Aug, 5, 1947 2,440,538 Chalberg Apr. 27, 1948 2,455,456 Whittaker Dec. 7, 1948 2,489,253 Andre Nov. 29, 1949 2,561,612 Culver July 24, 1951 

